Sectional furnace



Aug. 13, 1929. J, DOHERTY 1,724,462

I SECTIONAL FURNACE Filed March 21, 1923 $8.1 a Ii Alum I "N VENTOR Patented Aug. l3, 1329.

avatar earns errata.

JAMES DOHERTY, OF CHICAGO, ILLINOIS; ELLA ItIAUD DOHERTY AND JAMES RUSSELL DOHERTY EXECUTORS OF SAID JAIVIESDOHERTY, DECEASED.

SECTIONAL FURNACE.

Application filed March 21, 1923.

My invention relates to a sectional furnace of known type, which is made up of an assembled series of hollow water-containing sections and in which it is sought to procure complete combustion and to render the furnace smokeless by the introduction of auxiliary air, the structure and objects thus generally recited, being familiar in this art. My invention is concerned with the means for bringing about these results in the most effective manner, that is, for introducing the air at the proper place and in the best way and at a proper temperature, and involves associating the auxiliary air passage or passages in a furnace of the type stated with a water-containing bridge wall or with a water-containing bafiie wall in advance of the bridge wall and in the preferred form with both, and in providing supplementary mixing and combustion chamber formed in or by adjacent sections and located above the fuel space and preferably, at least in part over it, and just beyond the point of introduction of the auxiliary air. My invention also lies in the structure of certain sections, and in other features hereinafter pointed out.

- Referring to the drawings,

Fig. 1 is a side elevation partly in vertical section of a furnace embodying my invention;

Fig. 2 is a front elevation partly in section on line Ill-11 of Fig. 1;

Fig. 3 is a perspective view of the angle bar completing one of the auxiliary air passages; 1

Fig. 4- is a horizontal section on the line IV1V of Fig. 2, and

Fig. 5 is a detail section showing the essential parts of the preferred form of my invention. 7

The furnace in which the invention is illustrated is made up of a series of hollow water-containing sections 1, bolted together in the customary way andsuit-ably supported on a base comprised of the side members 2 which are connected by front and rear transverse plates 3 and 4c, and by an intermediate transverse division plate 5 which latter forms the rear of the ash pit. The front plate 4 carries the usual ash-pit door and damper arrangements, and fuel-feed and flue clean-out doors are provided as usual in the front section. The sections are interiorly shaped to form the firebox 6, rear Serial No. 626,484.

fiue space 7 in communication therewith, upper forward and return flues 8 and 9, and

the-firebox has a perforate grate, as indicated. Two of the intermediate sections, which I have designated respectively as 1 and 1 embody the novel features, whichby their presence and cooperation in the furnace combine to produce the results above alluded to. The section 1 is shaped to form the fire-bridge or rear wall 11 of the firebox, being as heretofore stated hollow and water-containing and defining by its upper edge the underside of the outlet opening of the supplementary combustion chamber 17 which will be more fully described hereinafter. This section is further provided with means for delivering air athwart the current of burning gases as it passes from the fire-box to the rear flue space 7. Such means consists of an air passage located near the upper part of the bridge wall and is constituted by a rabbet recess 12 formed in the cast bridge wall 11, preferably along its top front corner, and covered by a separately made member which most conveniently takes the form of an angle bar 13, secured removably in place by bolts, as indicated, or otherwise. This bar is provided with a continuous slot or a series of air delivery openings 14 in its front or vertical flange, and the passage formed between it and the bridge wall is open to atmosphere at its ends, through suitable openings cast in the side portions of the section 1 as will be understood. This section 1" also, has a water-containing wall portion 15 directly above the fire bridgell and air passage 12 which cooperates with the latter members to complete the outlet from the supplementary chamber 17 above referred'to. The furnace section 1 immediately in advance of the bridge wall section 1 is formed with a depending water-cooled baffle wall 16, the form of which may vary but which in Fig. 1 is an unbroken vertical water-curtain depending to about the level of the top of the fire bridge or slightly lower, and being forwardly spaced therefrom so as to form therewith an upward passage for the fire gases. With the adjacent parts of section 1*, this section 1 and its water curtain 16 also form a space 17 which may be termed a supplementary combustion chamber and which is of relatively small capacity as compared with the firebox, being located adjacent the top of the firebox, that is, between the firebox and the overhead flues. It will be noted that in addition to the main supply of combustion-supporting air entering through the perforate grate an auxiliary supply is also admitted through the air passage 12 and its distributing outlets 14, both under the pull of the chimney draft. The auxiliary air is thus delivered with considerable velocity forwardly into the current of burning gases passing the bridge wall and being heated by contact with the angle bar 18, has the effect of increasing and quickening the combustion reaction. 'The effect of the pocket or space formed by the supplementary combustion chamber 17 causes a more thorough intermixing of the air with the fire gases than would otherwise occur, there being a double change in direction of the gases during their passage into, through and out of said chamber with corresponding opportunity for more perfect combustion and a more eliicient utilization of the heat released. It will be understood, however, that there is no intention to imply any limitation of the units 1 or 1 to the particular forms which they have in the furnace illustrated, it being sufficient that they retain characteristics insuring the attainment of the objects: of the invention in a substantially similar way.

In the form illustrated in Fig. 5, the section 1" is the same as in Fig. 1. Section 1 is however modified by providing therear side of the depending wall 16 with a watercooled ledge o'r shelf 18 adjacent its lower edge. This shelf runs across the furnace and together with a removable cover member 19, preferably a removable angle bar exy the same as bar 13 and interchangeable each end of which air is admitted from atmosphere through openings cast in the sides of this section as in the case of section 1. This passage is preferably situated direct ly opposite the other air passage 12 and like the latter is formed by the cooper ion of the anglebar with a shouldered part of the casting. Its purpose is not so much to admit a larger amount of to the fire gases, as to provide better distributien of the limited amount that is needed for the unconsuined fuel. Regulation of the amount admitted is provided by the small dampers 20 car ried in the bushings 21 inserted in the encs of both air passages. It will be apparent that the fire-gas flow from the fire-box will be thoroughly mixed with well-heated auxiliary air, penetrating and mixing with it from opposite sides and that the chamber 17 affords opportunity, as before, for better mixing of the gases with the air, and it will be understood that by proper adjustmentof the air supply the furnace may be readily operated on bituminous coal wi '11 the intense smokeless combustion effect that h it, forms an auxiliary air passage to is characteristic of furnaces of this type,

Claims 1. A sectional furnace composed of an assembled series of cast hollow water-containing sections having a grate and forming a firebox and having a hollow water-containing baflle wall depending into the firebox, and a hollow water-containingbridge wall in rear of said baffle wall and horizontally spaced therefrom and between which and said baffle wall fire gases pass, said bridge wall having adjacent its front top corner an air passage having a forwardly facing outlet whereby air is delivered forwardly athwart the fire-gas flow.

2. A sectional furnace made up of an assembled series of transverse hollow watercontaining sections and having a grate and firebox, two adjacent sections of said series forming respectively a water-containing baille wall in the firebox and a water-containing bridge wall in rear thereof, and air delivering means associated with the rear of the ballle wall and with the front of the bridge wall and extending transversely of the furnace and each having means for distributing and delivering auxiliary air to the fire-gas flow.

3. A sectional furnace made up of an assembled series of hollow water-containing sections and having a grate and a firebox and a water-containing baffle wall therein having on its rear side adjacent its bottom, a rearwardly projecting water-containing ledge, rcmovably air delivery means associated with said ledge for forming an air passage along the same, through which auxiliary air is distributed to the fire-gas flow, and a bridge wall adjacent the ballie wall.

4. A sectional furnace composed of an assembled series of cast hollow, water-containing sections, having a grate and forming a firebox, two of said sections being adjacent and providing respectively a water-contain,

ing bafile wall depending into the firebox and a water-containing bridge wall upstanding in rear of and above said bafl'le wall and spaced therefrom and forming therewith an upward passage for the fire-gas flow, said walls having opposed portions of less thickness than the adjacent portions, thereby forming shoulders, and means associated with said reduced portions and shoulders forming therewith transverse air delivery passages, said means being adapted for heating and mixing air wit-h the fire-gas flow.

5. A sectional furnace made up of an assembled series of hollow water-containing sections and having a grate and a firebox, a watencontaining baffle wall depending into the firebox and having at its rear side adjacent the bottom a water protected ledge ex-' tending crosswise of the furnace and removable mcans for forming an air passage along said ledge having a rearwardly directed air distributing outlet therefrom, a hollow water-containing bridge wall in rear of said baffle wall and spaced therefrom and between which and said baffle Wall the fire gases pass, an air delivery passage adjacent the top front corner of the bridge wall and having forwardly delivering air openings, whereby auxiliary air is distributed through said outlet openings and delivered rearwardly and forwardly respectively across and into the fire gas flow. a

6. A sectional furnace composed of an assembled series of cast hollow water-containing sections, having a grate and forming a firebox and having a water-containing bafile wall depending into the fire-box, a Watercontaining bridge wall upstanding in rear of and above said bafiie wall and spaced therefrom and forming therewith an upward passage for the fire-gas flow, the front of said bridge wall and the rear of said baffle wall being provided with opposed air delivery passages extending transversely along said walls and interchangeable angle bars provided with delivery openings in their opposed faces and completing the re spective delivery passages whereby air is delivered to front and rear across the fire gas flow.

7. A sectional furnace made up of an assembled series of cast hollow water-containing sections having spaces constituting respectively a firebox provided with a bridge wall, and a supplemental combustion chamber having a depending wall in front of and spaced from the bridge wall, said supplemental combustion chamber being located adjacent the upper part of the firebox near the bridge wall and in communication with the firebox adjacent the bottom of the chamber by a vertical passage between the depending wall and the bridge wall, the outlet of the chamber being a horizontal passage and said chamber having a downwardly projecting water-cooled wall which assists in defining the outlet, and means for delivering auxiliary air to the fire gas flow adjacent the inlet of the chamber, the construction described furnishing a pocket in the upper part of the chamber and by reason of the relative arrangement of inlet and outlet specified insuring change of direction and consequently mixing of the fire gases and auxiliary air as they pass through the chamber.

8. A sectional furnace made up of an assembled series of transverse hollow watercontaining sections having a grate and forming a firebox and flue space in rear of and in communication therewith, and overhead return lines above said firebox and flue space and in communication with the latter, intermediate sections forming by water-cooled walls a supplemental combustion chamber defined in part by a depending water-cooled wall in front of and spaced from the bridge wall, said chamber overhanging the rear part of the firebox, having a'downwardly opening 7 fire gas inlet therefrom and located near the and means for distributing and delivering 1 air to the fire gases as they pass from the firebox up into the supplementary combustion chamber.

9. A sectional furnace composed of a series of hollow water-containing sections having a grate and forming a firebox, a hollow watercontaining bafile wall depending into the firebox near the rear thereof, a hollow watercontaining bridge wall in rear of said baffle wall and horizontally spaced therefrom and between which and said baffle wall the fire gases fiow, a supplementary water-backed combustion chamber of relatively moderate dimensions as compared with the firebox and in communication therewith located immediately in rear of said baffle wall and above the fuel space, and an air delivery passage associated with the bridge wall adjacent its top and extending crosswise of the furnace for delivering auxiliary air across the fire gas fiow as it passes into said supplementary combustion chamber. 1

10. A sectional furnace made up of an assembled series of cast hollow Water-containing sections and having a grate and a firebox, a hollow water-containing baflie wall depending into the firebox, and having at its rear side adjacent the bottom thereof a water protected ledge and removable means forming an air passage along said ledge for auxiliary air having-a rearwardly opening outlet, a hollow water-containing bridge wall upstanding in rear of said bafile wall and spaced therefrom and forming therewith an upward passage for the fire-gas flow, an air delivery passage adjacent the top of the bridge wall at its front side for delivering auxiliary air, having forwardly facing outlets, and a supplementary water-cooled combustion chamber of relatively moderate dimensions compared with the firebox and in communication therewith through the space between the baffle wall and bridge wall, said supplementary combustion chamber being immediately in rear of said baffle wall.

11. In a sectional furnace composed of a series of transverse hollow water-containing sections, a supplemental combustion chamber having restricted inlet and outlet and formed by two adjacent sections said supplemental combustion chamber extending across the furnace and having water-containing walls, and means associated with at least one of said sections for delivering air adjacent the inlet of said chamber.

12. In a sectional furnace, a cast hollow watencontaining section having at its lower part a hollow water-containing bridge wall, a fire-gas passage above the same, overhead flue openings separated from said fire-gas opening by a transverse water-containing portion having a downwardly projecting wall over the bridge wall, defining therewith the fire gas passage, of less depth than the bridge wall and displaced rearward of its front face to provide fire gas space over 10 the bridge wall, said bridge wall having associated therewith means forming therewith a forwardly delivering air duct extending across the section.

In testimony whereof, I have signed this 15 specification.

JAMES DOHERT'Y. 

